A. Field of the Invention
The invention involves a microscope, in particular an operation microscope.
B. Description of the Prior Art
The prior art knows two main groups of microscopes:
(1) one-tube monocular microscopes and PA1 (2) two-tube stereomicroscopes.
Adjusting elements for the optical components of the microscope and/or for work tables are known for both variants.
Since the user as a rule concentrates on observing the object viewed through the microscope, such adjusting elements must be situated in the area between the objective and the eyepiece, so that the user can reach them well.
In various applications, in particular, however, in operation microscopes, it is difficult for a user (operating surgeon) to operate the microscope in this way, since, as a rule, he needs both hands to carry out the operation or the manipulation of the object. To make things easier for the users in such situations, electrically driven adjusting elements were developed that undertook the desired settings or adjustments via a remote control (electric switch). In order to free the user's hands completely, foot switches with which various limited adjustments, such as zoom, focus, etc., could be undertaken were attached to the microscope.
In operations in particular, however, it is not easy for a user who is concentrating on a field of view and his hands to coordinate additional movements of his feet to operate various foot switches or the like. Therefore in the course of extensive further developments voice-operated adjustment elements were created that were operated by the user by means of speech. Speech-recognition software is not yet free of errors, however, and especially in the stress of an operation there is the danger that an operating error of the microscope could occur through a misinterpretation of a command, which could have catastrophic consequences for the patient in certain difficult operations. In addition, the speech-recognition software as a rule is not suitable for understanding different users or must store the speech profiles of all users through extensive voice rehearsals, which means considerable costs and reduces the availability of the microscope. Mouth switches were also developed that in the first place were uncomfortable and in the second place could hardly be used with the necessary oral protection.
Obviously various eye-tracking methods are known. Since the beginning of 1994 at least the camera for autofocussing of the Canon company that was mentioned has been known. A French report "Informatique 92" developed a complete system as of 1992 in which a microscope is controlled by means of eye-tracking in such a way that when an operating surgeon changes his direction of sight through the tube (e.g. he looks to the left), the microscope changes its position in space and orients or swings the tubes to the new direction of sight of the operating surgeon. This procedure is not used in practice, since it is often not at all desired by the operating surgeon possibly to lose what had previously been seen from the angular field. In addition, the automatic adjustment of the microscope in accordance with this known teaching leads to the fact that the microscope, which was originally focussed correctly, can suddenly become unfocussed in the center of its direction of sight, since as a rule the Z distance also changes through the swivelling of the tubes. Only at low magnifications or in microscopes with built-in external autofocussing (not eye-oriented) could this system possibly find practical application.
A Japanese publication JP-A-51108252 refers to an eye-controlled cursor in a computer as of 1993. As a user looks at a computer monitor, he is watched, so that his eye movements can control what happens on the screen. This prior art, however, lies outside microscopy, and it also does not provide any indication of the teaching in accordance with the invention. The control of microscope drives or something like that is not suggested. The same is true for U.S. Pat. No. 4,973,149, which previously proposed watching the user's eyes while looking at a computer monitor and so giving the user the possibility of controlling the computer or his environment. WO-A-93/14454, which also dates from 1993, refers to the control of a computer monitor by means of eye-tracking.